Re: [PATCH v5 5/7] drm/aspeed: Add reset and clock for AST2600

Joel Stanley
2022-03-01T11:05:11Z

On Tue, 1 Mar 2022 at 07:00, Tommy Huang <tommy_huang@aspeedtech.com> wrote:
>
> Hi Joel,
>
> It seems that the reset control could keep original code behavior.
> Just change the reset define in the .dtsi file from ASPEED_RESET_CRT1 into ASPEED_RESET_GRAPHICS.

Right, because the ASPEED_RESET_CRT reset is released by the
ASPEED_CLK_GATE_D1CLK line?

include/dt-bindings/clock/ast2600-clock.h:#define ASPEED_RESET_CRT
13

drivers/clk/clk-ast2600.c: /*
clk rst name parent flags */
drivers/clk/clk-ast2600.c: [ASPEED_CLK_GATE_D1CLK] = {
10, 13, "d1clk-gate", "d1clk", 0 >

>
> By the way, the HW controller states and FW programming register will be reset by CRT reset line.
> And another part HW controller states will be reset by engine reset line.

Thanks. Can we include that in the commit message for the device tree change?

>
> Thanks,
>
> By Tommy
>
> > -----Original Message-----
> > From: Joel Stanley <joel@jms.id.au>
> > Sent: Monday, February 28, 2022 5:51 PM
> > To: Tommy Huang <tommy_huang@aspeedtech.com>
> > Cc: David Airlie <airlied@linux.ie>; Daniel Vetter <daniel@ffwll.ch>; Rob
> > Herring <robh+dt@kernel.org>; Andrew Jeffery <andrew@aj.id.au>;
> > linux-aspeed <linux-aspeed@lists.ozlabs.org>; open list:DRM DRIVERS
> > <dri-devel@lists.freedesktop.org>; devicetree <devicetree@vger.kernel.org>;
> > Linux ARM <linux-arm-kernel@lists.infradead.org>; Linux Kernel Mailing List
> > <linux-kernel@vger.kernel.org>; BMC-SW <BMC-SW@aspeedtech.com>
> > Subject: Re: [PATCH v5 5/7] drm/aspeed: Add reset and clock for AST2600
> >
> > On Wed, 8 Dec 2021 at 01:34, Tommy Haung
> > <tommy_huang@aspeedtech.com> wrote:
> > >
> > > From: tommy-huang <tommy_huang@aspeedtech.com>
> > >
> > > Add more reset and clock select code for AST2600.
> > > The gfx_flags parameter was added for chip caps idenified.
> >
> > Can you tell me a bit more about the two reset lines:
> >
> > What is the CRT reset line controlling?
> >
> > What does the engine reset line control?
> >
> > Can we use devm_reset_control_array_get() to get whichever are specified in
> > the device tree, so we don't need to have different logic for the 2600 and
> > earlier chips?
> >
> >
> >
> > >
> > > Signed-off-by: tommy-huang <tommy_huang@aspeedtech.com>
> > > ---
> > > drivers/gpu/drm/aspeed/aspeed_gfx.h | 16 +++++++-
> > > drivers/gpu/drm/aspeed/aspeed_gfx_crtc.c | 16 ++++++++
> > > drivers/gpu/drm/aspeed/aspeed_gfx_drv.c | 50
> > ++++++++++++++++++++++--
> > > 3 files changed, 77 insertions(+), 5 deletions(-)
> > >
> > > diff --git a/drivers/gpu/drm/aspeed/aspeed_gfx.h
> > > b/drivers/gpu/drm/aspeed/aspeed_gfx.h
> > > index 4e6a442c3886..2c733225d3c7 100644
> > > --- a/drivers/gpu/drm/aspeed/aspeed_gfx.h
> > > +++ b/drivers/gpu/drm/aspeed/aspeed_gfx.h
> > > @@ -8,7 +8,8 @@ struct aspeed_gfx {
> > > struct drm_device drm;
> > > void __iomem *base;
> > > struct clk *clk;
> > > - struct reset_control *rst;
> > > + struct reset_control *rst_crt;
> > > + struct reset_control *rst_engine;
> > > struct regmap *scu;
> > >
> > > u32 dac_reg;
> > > @@ -16,6 +17,7 @@ struct aspeed_gfx {
> > > u32 vga_scratch_reg;
> > > u32 throd_val;
> > > u32 scan_line_max;
> > > + u32 flags;
> > >
> > > struct drm_simple_display_pipe pipe;
> > > struct drm_connector connector;
> > > @@ -106,3 +108,15 @@ int aspeed_gfx_create_output(struct drm_device
> > > *drm);
> > > /* CRT_THROD */
> > > #define CRT_THROD_LOW(x) (x)
> > > #define CRT_THROD_HIGH(x) ((x) << 8)
> > > +
> > > +/* SCU control */
> > > +#define SCU_G6_CLK_COURCE 0x300
> > > +
> > > +/* GFX FLAGS */
> > > +#define RESET_MASK BIT(0)
> > > +#define RESET_G6 BIT(0)
> > > +#define CLK_MASK BIT(4)
> > > +#define CLK_G6 BIT(4)
> > > +
> > > +#define G6_CLK_MASK (BIT(8) | BIT(9) | BIT(10))
> > > +#define G6_USB_40_CLK BIT(9)
> > > diff --git a/drivers/gpu/drm/aspeed/aspeed_gfx_crtc.c
> > > b/drivers/gpu/drm/aspeed/aspeed_gfx_crtc.c
> > > index 827e62c1daba..e0975ecda92d 100644
> > > --- a/drivers/gpu/drm/aspeed/aspeed_gfx_crtc.c
> > > +++ b/drivers/gpu/drm/aspeed/aspeed_gfx_crtc.c
> > > @@ -77,6 +77,18 @@ static void aspeed_gfx_disable_controller(struct
> > aspeed_gfx *priv)
> > > regmap_update_bits(priv->scu, priv->dac_reg, BIT(16), 0); }
> > >
> > > +static void aspeed_gfx_set_clk(struct aspeed_gfx *priv) {
> > > + switch (priv->flags & CLK_MASK) {
> > > + case CLK_G6:
> > > + regmap_update_bits(priv->scu, SCU_G6_CLK_COURCE,
> > G6_CLK_MASK, 0x0);
> > > + regmap_update_bits(priv->scu, SCU_G6_CLK_COURCE,
> > G6_CLK_MASK, G6_USB_40_CLK);
> > > + break;
> > > + default:
> > > + break;
> > > + }
> > > +}
> > > +
> > > static void aspeed_gfx_crtc_mode_set_nofb(struct aspeed_gfx *priv) {
> > > struct drm_display_mode *m =
> > > &priv->pipe.crtc.state->adjusted_mode;
> > > @@ -87,6 +99,8 @@ static void aspeed_gfx_crtc_mode_set_nofb(struct
> > aspeed_gfx *priv)
> > > if (err)
> > > return;
> > >
> > > + aspeed_gfx_set_clk(priv);
> > > +
> > > #if 0
> > > /* TODO: we have only been able to test with the 40MHz USB
> > clock. The
> > > * clock is fixed, so we cannot adjust it here. */ @@ -193,6
> > > +207,7 @@ static void aspeed_gfx_pipe_update(struct
> > > drm_simple_display_pipe *pipe, static int
> > > aspeed_gfx_enable_vblank(struct drm_simple_display_pipe *pipe) {
> > > struct aspeed_gfx *priv = drm_pipe_to_aspeed_gfx(pipe);
> > > +
> > > u32 reg = readl(priv->base + CRT_CTRL1);
> > >
> > > /* Clear pending VBLANK IRQ */ @@ -207,6 +222,7 @@ static int
> > > aspeed_gfx_enable_vblank(struct drm_simple_display_pipe *pipe) static
> > > void aspeed_gfx_disable_vblank(struct drm_simple_display_pipe *pipe)
> > > {
> > > struct aspeed_gfx *priv = drm_pipe_to_aspeed_gfx(pipe);
> > > +
> > > u32 reg = readl(priv->base + CRT_CTRL1);
> > >
> > > reg &= ~CRT_CTRL_VERTICAL_INTR_EN; diff --git
> > > a/drivers/gpu/drm/aspeed/aspeed_gfx_drv.c
> > > b/drivers/gpu/drm/aspeed/aspeed_gfx_drv.c
> > > index d10246b1d1c2..59a0de92650f 100644
> > > --- a/drivers/gpu/drm/aspeed/aspeed_gfx_drv.c
> > > +++ b/drivers/gpu/drm/aspeed/aspeed_gfx_drv.c
> > > @@ -64,6 +64,7 @@ struct aspeed_gfx_config {
> > > u32 vga_scratch_reg; /* VGA scratch register in SCU */
> > > u32 throd_val; /* Default Threshold Seting */
> > > u32 scan_line_max; /* Max memory size of one scan line */
> > > + u32 gfx_flags; /* Flags for gfx chip caps */
> > > };
> > >
> > > static const struct aspeed_gfx_config ast2400_config = { @@ -72,6
> > > +73,7 @@ static const struct aspeed_gfx_config ast2400_config = {
> > > .vga_scratch_reg = 0x50,
> > > .throd_val = CRT_THROD_LOW(0x1e) | CRT_THROD_HIGH(0x12),
> > > .scan_line_max = 64,
> > > + .gfx_flags = 0,
> > > };
> > >
> > > static const struct aspeed_gfx_config ast2500_config = { @@ -80,6
> > > +82,7 @@ static const struct aspeed_gfx_config ast2500_config = {
> > > .vga_scratch_reg = 0x50,
> > > .throd_val = CRT_THROD_LOW(0x24) | CRT_THROD_HIGH(0x3c),
> > > .scan_line_max = 128,
> > > + .gfx_flags = 0,
> > > };
> > >
> > > static const struct aspeed_gfx_config ast2600_config = { @@ -88,6
> > > +91,7 @@ static const struct aspeed_gfx_config ast2600_config = {
> > > .vga_scratch_reg = 0x50,
> > > .throd_val = CRT_THROD_LOW(0x50) | CRT_THROD_HIGH(0x70),
> > > .scan_line_max = 128,
> > > + .gfx_flags = RESET_G6 | CLK_G6,
> > > };
> > >
> > > static const struct of_device_id aspeed_gfx_match[] = { @@ -138,6
> > > +142,44 @@ static irqreturn_t aspeed_gfx_irq_handler(int irq, void *data)
> > > return IRQ_NONE;
> > > }
> > >
> > > +static int aspeed_gfx_reset(struct drm_device *drm) {
> > > + struct platform_device *pdev = to_platform_device(drm->dev);
> > > + struct aspeed_gfx *priv = to_aspeed_gfx(drm);
> > > +
> > > + switch (priv->flags & RESET_MASK) {
> > > + case RESET_G6:
> > > + priv->rst_crt = devm_reset_control_get(&pdev->dev,
> > "crt");
> > > + if (IS_ERR(priv->rst_crt)) {
> > > + dev_err(&pdev->dev,
> > > + "missing or invalid crt reset controller
> > device tree entry");
> > > + return PTR_ERR(priv->rst_crt);
> > > + }
> > > + reset_control_deassert(priv->rst_crt);
> > > +
> > > + priv->rst_engine = devm_reset_control_get(&pdev->dev,
> > "engine");
> > > + if (IS_ERR(priv->rst_engine)) {
> > > + dev_err(&pdev->dev,
> > > + "missing or invalid engine reset
> > controller device tree entry");
> > > + return PTR_ERR(priv->rst_engine);
> > > + }
> > > + reset_control_deassert(priv->rst_engine);
> > > + break;
> > > +
> > > + default:
> > > + priv->rst_crt =
> > devm_reset_control_get_exclusive(&pdev->dev, NULL);
> > > + if (IS_ERR(priv->rst_crt)) {
> > > + dev_err(&pdev->dev,
> > > + "missing or invalid reset controller
> > device tree entry");
> > > + return PTR_ERR(priv->rst_crt);
> > > + }
> > > + reset_control_deassert(priv->rst_crt);
> > > + break;
> > > + }
> > > +
> > > + return 0;
> > > +}
> > > +
> > > static int aspeed_gfx_load(struct drm_device *drm) {
> > > struct platform_device *pdev = to_platform_device(drm->dev);
> > > @@ -163,6 +205,7 @@ static int aspeed_gfx_load(struct drm_device *drm)
> > > priv->vga_scratch_reg = config->vga_scratch_reg;
> > > priv->throd_val = config->throd_val;
> > > priv->scan_line_max = config->scan_line_max;
> > > + priv->flags = config->gfx_flags;
> > >
> > > priv->scu = syscon_regmap_lookup_by_phandle(np, "syscon");
> > > if (IS_ERR(priv->scu)) {
> > > @@ -186,13 +229,12 @@ static int aspeed_gfx_load(struct drm_device
> > *drm)
> > > return ret;
> > > }
> > >
> > > - priv->rst = devm_reset_control_get_exclusive(&pdev->dev, NULL);
> > > - if (IS_ERR(priv->rst)) {
> > > + ret = aspeed_gfx_reset(drm);
> > > + if (ret) {
> > > dev_err(&pdev->dev,
> > > "missing or invalid reset controller device tree
> > entry");
> > > - return PTR_ERR(priv->rst);
> > > + return ret;
> > > }
> > > - reset_control_deassert(priv->rst);
> > >
> > > priv->clk = devm_clk_get(drm->dev, NULL);
> > > if (IS_ERR(priv->clk)) {
> > > --
> > > 2.17.1
> > >